This invention relates generally to the electrical control systems for controlling the action of a circuit breaker and it relates specifically to modular control systems utilizing plug-in modules which are universally adaptable for use over a wide range of current values.
In the past it has been known to provide circuit breaker control systems utilizing a multitude or a number of current and voltage sensors to control functions such as inverse time overload to thereby cause a circuit breaker to trip. Sometimes a separate circuit breaker is provided for each function to be controlled. Sometimes it is necessary to provide a multitude of current sensors each adapted to sense different ranges of currents or different values of currents or different rates of change of currents or voltage to in turn supply that information to a logic device which in turn can cause a certain circuit breaker to trip. Devices of this kind are described in U.S. Pat. No. 3,713,005 entitled "Circuit Breaker Including Improved Overcurrent Protective Device" issued on Jan. 23, 1973 to J. C. Engel and assigned to the same assignee as the assignee of the present invention, and in technical bulletin 980 of June 1972 entitled "Phase Failure Relays" by the Wilmar Electronics, Inc. of 2103 Border Avenue, Torrance, California and in a technical bulletin 948-B1 of June 1971, entitled "Overload Relays" by the Furnas Electric Company of Batavia, Illinois. It would be advantageous if a universal control system for a circuit breaker could be found which is utilizable over a wide range of circuit currents and voltage conditions and which is adaptable to utilize plug-in logic modules to control or cause the circuit breaker to trip in response to a variety of different kinds of circuit functions.